The invention relates to switch arrays for use in computer input devices and, more particularly, to keyboards and keypads.
Electronic switches are used to provide input to computer devices. Electronic switches generate signals in response to physical force. For example, a user may actuate an electronic switch by pressing a key. Pressing the key causes a force to be applied on an electronic membrane, which in turn causes the electronic membrane to generate an electronic signal. A computer keyboard is one common example of a switch array.
Many switch arrays, such as keyboards, include dome spring elements to provide a biasing force against individual keys. Dome spring elements provide tactile feedback to a user by providing a defined amount of resistance to key actuation. Moreover, dome spring elements may provide a xe2x80x9csnappingxe2x80x9d feel upon actuation, wherein the amount of resistance to key actuation drastically decreases after pressing the key past a threshold distance.
Dome spring elements can become contaminated, however, particularly if liquid collects under or within the dome spring elements. When this happens, the resistance of the spring can change, and the xe2x80x9csnappingxe2x80x9d feel can be lost. Moreover, individual spring elements can become stuck in an actuated position. These phenomena are often referred to as xe2x80x9csticky keyxe2x80x9d phenomena.
In general, the invention is directed to various apparatuses for use in switch arrays such as computer keyboards or keypads. In one embodiment, the invention provides an array of dome spring elements for use in a switch array. Each of the dome spring elements defines a chamber. A plurality of channels may interconnect the chambers of the dome spring elements such that each chamber of each dome spring element is in fluid communication with the chamber of at least one of the other dome spring elements. This is advantageous because it allows for key-to-key venting. In addition, the regions between the various dome spring elements may have no holes, thus providing a hermetic barrier to the back side of the individual dome spring elements. This is advantageous because the array of dome spring elements can seal off the individual dome spring elements from the outside environment to avoid the sticky key phenomenon.
In another embodiment, the invention provides a set of alignment elements for use in a switch array. The set of alignment elements may include a bottom layer defining holes for aligning with spring elements, and a top layer engaged with the bottom layer. The top layer is biased away from the bottom layer upon protrusion of spring elements through the holes in the bottom layer. The top and bottom layers may be films that include hook-like elements that engage one another. In this manner, the top and bottom layers can define a predetermined amount of key travel. Moreover, the predetermined amount of key travel may be less than the amount of key travel of conventional keyboards that implement scissors hinges. In addition, the set of alignment elements can provide resistance to key rocking.
One or more aspects of the invention may be used to realize thinner keyboards, and or keyboards that have fewer elements. For example, in one embodiment, the top layer of the set of alignment elements defines keys without the use of additional keycaps. In addition, the invention may provide easier keyboard manufacturing and assembly, and therefore, may lower production costs associated with the manufacturing of keyboards. Also, the invention may result in switch arrays that are flexible, rollable, washable, submersible, or otherwise more useful for various applications.
Additional details of various embodiments are set forth in the accompanying drawings and the description below. Other features, objects and advantages will become apparent from the description and drawings, and from the claims.